Anatomy and Physiology
Your blood carries oxygen and nutrients to all of your tissues and removes carbon dioxide and other waste products from your tissues. It also helps fight infection and heal wounds.

Blood consists of a liquid portion and cellular components. The liquid, called plasma, is where nutrients, hormones, clotting factors, and other chemicals are dissolved.

The cellular components are suspended, rather than dissolved, in the plasma. They consist of: Red blood cells, which transport oxygen and carbon dioxide; white blood cells, which fight infection; platelets, which are really just small subcells that help the blood to clot.

Blood cells are made in the bone marrow, a soft tissue housed inside many of your bones. Your vertebrae, ribs, hips, skull, breastbone, shoulders, and pelvis contain most of your body's bone marrow.

Reasons for Procedure
A blood transfusion is performed to treat a medical condition or to save your life. It uses donor blood to replenish red blood cells, white blood cells, platelets, clotting factors, plasma, or whole blood. Since blood is the equivalent of an organ, transfusion of blood or blood components from one person to another should be thought of as an organ transplant.

Circumstances that may require a blood transfusion include: blood loss due to trauma, heart or other major surgery, organ transplants, bleeding disorders such as hemophilia, severe anemia, including sickle cell anemia, leukemia or other cancer treatment, and disorders that destroy blood cells or bone marrow Rh-incompatibility in newborn babies.

Treatments
In major surgery, trauma, or other cases of extreme blood loss, your doctor may need to perform a blood transfusion to save your life. Blood transfusions can also stabilize medical conditions that affect your supply of whole blood or its components.

For a blood transfusion, an adequate supply of compatible blood must be available. Blood transfusions generally come from one of four sources: anonymous volunteer donors, directed donation by your family members or friends, your own blood, collected in the weeks before your surgery, your own blood, collected and recycled during or after your surgery. Using your own blood is ideal, since it avoids the potential problems associated with incompatible blood types, allergic reactions, and the spread of infection.

Using a process called aphersis, doctors are able to separate out the various components of blood and transfuse each of them selectively to treat different medical conditions. This allows many more people to benefit from each unit of separated whole blood. Apheresis donations take considerably longer than regular blood donations.

Procedure
If you know in advance that you may need a blood transfusion, your doctor will discuss special instructions and precautions regarding your diet and medications. Also, do not start taking new medications, herbs, or dietary supplements without first consulting your doctor.

Before the transfusion, you will have a blood test to match your blood type to the correct donor blood. There are four major blood types: A, B, AB, and O. In addition, each blood type is given a positive or negative designation indicating the presence or absence of the so-called Rh factor. Any individual can accept blood from a Type-O donor, but a Type-A individual, for example, cannot safely accept blood from a Type-B donor.

Before your transfusion, your vital signs will be checked, and you may be given acetaminophen and an antihistamine to reduce the risk of an allergic reaction. The nurse or technician will then double check your identification bracelet with the label on the blood to be sure that you are receiving the correct blood type.

A blood transfusion generally takes 2-4 hours. To begin the transfusion, an intravenous needle will be inserted into a vein in your hand or arm.

A bag containing the donor blood will be hung nearby, and the blood will drip slowly through a tube attached to the IV needle, allowing it to run through your vein, into your bloodstream.

Throughout the transfusion, your temperature, heart rate, breathing, and blood pressure will be monitored. You will be asked if you feel any pain, itching, or discomfort. If you develop an allergic reaction to the blood, the transfusion may be stopped and you will likely be given antihistamines to control the reaction.

After the bag is empty, if you require more blood, another bag will be attached to the IV tube. A double cross checking procedure will be followed to avoid any possibility of transfusion errors. After your transfusion is complete, the needle will be removed.

Risks and Benefits
Although rare, whenever receiving blood or blood components from another person there is a chance of a blood type mismatch. This usually occurs due to a clerical error or mislabeled specimen, which are extremely unlikely occurrences in most hospitals.

Recipients of any type of blood transfusion from another person may also develop an allergic reaction. Symptoms may include fever, itchiness, hives, and/or shortness of breath in severe cases.

Although careful testing of the U.S. blood supply has greatly reduced this risk, it is possible that certain infections may be transmitted during a blood transfusion, including: Hepatitis B and C, Human immunodeficiency virus, or HIV, West Nile virus, and Syphilis.

In a blood transfusion, or any other procedure, you and your doctor must carefully weigh the risks and benefits to determine whether it is the most appropriate treatment choice for you.

After the Procedure
After your transfusion, your doctor will monitor your vital signs to make sure you are not having an adverse reaction. If necessary, you may be given a diuretic to reduce any swelling or fluid retention.

Your doctor will take blood tests to verify the success of the transfusion or determine the cause of any problems should they arise. Depending on the condition that required a transfusion, your doctor will give you specific instructions regarding what activities you may resume and when.

Once you are home, call your doctor promptly if you experience: dizziness or lightheadedness, signs of infection, including fever and chills, shortness of breath and/or wheezing, new onset of pain, especially in your back or chest, redness, swelling, pain, bleeding, and/or discharge where the needle was inserted, a new rash, hives, or itching; nausea and vomiting, blood in your urine, swelling in your legs, feet, hands, arms, and/or face.

Sources:

All about blood: FAQs. American Association of Blood Banks website. Available at: http://www.aabb.org/All_About_Blood/FAQs/aabb_faqs.htm. Accessed October 5, 2004.

Receiving a blood transfusion: what every patient should know. American Association of BloodBanks website. Available at: http://www.aabb.org/All_About_Blood/Receiving_Blood/receive.htm. Accessed October 5. 2004.

Medical Legal Art creates medical demonstrative evidence (medical
illustrations, drawings, pictures, graphics, charts, medical animations,
anatomical models, and interactive presentations) for use during legal
proceedings, including research, demand letters, client conferences,
depositions, arbitrations, mediations, settlement conferences, mock jury
trials and for use in the courtroom. We do not provide legal or medical
advice. If you have legal questions, you should find a lawyer with whom you
can discuss your case issues. If you have medical questions, you should seek the advice of a healthcare provider.